Relay system



C. LE G. FORTESCUE.

RELAY SYSTEM.

APPLICATION FILED SEPT-9,1916. 1,376,418. at ted May 3, 1921.

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INVENTOR flaw/8.5 LeQfZr/escae.

g BY ,1 9 ATTORNEY UNITED STATES PATENT OFFICE.

CHARLES LE G. FORTESCUE, OF IITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WEsT-INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

RELAY SYSTEM.

Specification of Letters Patent.

Patented May 3, 1921.

To all whom it may concern:

Be it known that I, CHARLES Ln G. FoR'rnscUE, a subject of the King ofEngland, and a resident of Pittsburgh, 1n the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inRelay Systems, of whlch the following is .a specification.

invention relates to relay systems and particularly to means forprotectlng parallel-connected feeder circuits.

One object of my invention is to provide a system of the above indicatedcharacter that shall have means for selectively disconnecting a feedercircuit when a ground or an overload occurs thereon.

Another object of my invention is to rovide a system of the aboveindicated 0 aracter that shall have means for disconnecting a feedercircuit when the product of the current traversing that circuit and thetotal current traversing all of the circuits exceeds a predeterminedvalue.

A further object of my invention is to provide a system of the aboveindicated character that shall operate correctly irrespective of thedirection of flow of energy therein.

In the carrying out of my invention, I provide a relay for eachinterrupter of a parallel-connected feeder circuit and cause one windingof each relay to be sup-plied with current proportional to the totalcurrent traversing all'of the circuits and the other Winding of eachrelay with current proportional to the current traversing its respectivefeeder circuit. The windings of the relays are so arranged that eachrelay develops sufficient torque to trip its interrupter only when thecurrent traversing its respective feeder circuit bears a predeterminedrelation to the total current traversing all of the feeder circuits,such as may render the rents traversing the circuits are equal and lessthan a predetermined value. or, when the currents are unequal but theproduct of the sum of the currents by the value of the current in anycircuit is less than a predetermmed value, the interrupter will not betripped. Thus, if one feeder circuit becomes grounded, the current willincrease in one of the windings of the relay to permit t to operate.Also, if one feeder circuit is excessively overloaded, the torque of therelay in the overloaded circuit will increase to such value as to causeits interrupter to trip.

' f the direction of flow of energy in all the parallel-connected feedercircuits reverses because of the regeneration of energy the relays willnot operate until a ground or overload occurs-on one or more of thecircults. Thus, the system is particularly adaptable to railway systemsin which the energy 1s frequently regenerated and returned to thesystem.

' In the accompanying drawings, Figure 1 1s a dlagrammatic view of arelay system embodylng my lnvention, and Fig. 2 is a diagrammatic viewof a system of distribution embodying myinvention.

A system in connection with which my invention may be used comprises agenerator 1 that is operatively connected to the primary winding 2 of atransformer 3 the secondary winding 4 of which is connected to atransmission circuit 5. Transformers 6, 7 and 8 are operativelyconnected to the adapted to be normally traversed by equalamounts ofcurrent. However, since they are connected, at predetermined points, toa trolley conductor (not shown), occasions arise when one conductor istraversed by relatively more current than the others. Also, any one ormore of the conductors may become grounded, and, if such. conditionsobtain, it is advisable to disconnect the faulty conductor or the faultyportion of it from the circuit. In view of the above, the feederconductors are arranged in sec.-

tions 14, 15 and 16 the respective ends of which are provided withcircuit interrupters 17, 18, 19, 20 and 21..

In order to cause the circuit interrupters 17, 18, 19, 20 and 21 to beselectively tripped when a ground occurs upon any one or more of thefeeder conductors, or when any one or n feeder conductor.

more of the feeder conductors becomes excessively overloaded, I providea relay system 22 for each set of interrupters that comprises, in

general, four relays 23, 24, 25 and 26 and four transformers 27, 28, 29and 30.

The relays 23, 24, 25 and 26 severally comprise a magnetizable coremember 31, two cotiperating windings 32 and 33, and an armature 34 thatis mounted upon a shaft 35 upon which is also mounted a bridging contactmember 36 and one end of a spring 41 the other end of which is connectedto a stationary member 42. The windings 32 are connected in series andadapted to be so connected to the transformers 27, 28, 29 and 30 as tobe supplied with current proportional to the sum of the currentstraversing the feeder conductors 10, 11, 12 and 13, and the winding 33of each of the relays-is adapted to be so connected to its respectivetransformer as to be supplied with current proportional to the currenttraversing its respective That is, the winding 33 ofthe relay 23 isconnected to the transformer 27, the winding 33 of the relay 24 isconnected to the transformer 28 and, similarly, the windings 33 of therelays 25 and 26 are connected to transformers 29 and 30, respectively.

The bridging contact member 36 of the relay 23 is adapted to engagestationary contact members 37 for the purpose of completing a circuitthrough a source 38 of electromotlve force and the trip coil 39 of itsrespective circuit interrupter. Similarly, the other bridging contactmembers 36 are ada ted to engage stationary contact members 3 for thepurpose-of completing the circuit of their respective trip coils 39.Each group of circuit interrupters 17, 18, 19, 20 and 21 is providedwith a relay system 22 in order that one or both ends of the conductorsmay be selectively and automatically disconnected from the remainder ofthe system under predetermined conditions.

Normally, each conductor of the feeder circuits carries the same amountof current which may be assumed to be I amperes, for purposes ofillustration. Under this condition, the torque developed by each of thearmatures is proportional to 4P. Hence, the springs 41 are of suchdimensions that when the currents traversing any one or more of thewindings 32 and 33 are such that the torque developed by the armatureexceeds, by a predetermined amount, the

Assume that the section 15 of the feeder conductors is not deliveringenergy to any apparatus in that section and that the conductor 10becomes grounded at a point 40 relatively nearer to the transformer 8than to the transformer 7. When such conditions obtain, the current willincrease in that part of the conductor 10 between the point 40 and theinterrupter 20 in inverse ratio to the distance of the point 40 from thetransformer 8. This will-cause the current traversing the Winding 33 ofthe relay 23 that is adapted to control the interrupter 20 to' increase.The total current traversing the conductors may remain constant orincrease because of the ground, depending upon whether or not load isbeing taken from the section, and, consequently, the current traversingthe winding 32 will either remain constant or increase. Thus, the torquedeveloped by the armature 34 will be relatively greater than the countertorque of the spring 41, and the bridging contact member 36 will engagethestationary contact members 37 to cause the trip coil 39 to open theinterrupter 20 of the conductor 10.

When the interrupter 20 of the conductor 10 is opened, the current willgreatly increase in the other portion of the conductor 10 in the section15, and, if the current traversing the conductors 11, 12 and 13 remainsconstant, increases or slightly decreases, the relay 23 of the system 22that controls the interrupter 19 will operate to thus completelydisconnect the conductor 10 in the section 15.

If a load is connected to one of the conductors of the section 14 and itdrawsan excessive current, the interrupter to which it is the closestwill trip if the product of the total current and the current throughthe overloaded conductor exceeds a predetermined value. If the "overloadpersists, the interrupter at the other end of the conductors will besimilarly disconnected, and the other conductors will be successivelydisconnected, in accordance with the relative the relative direction ofcurrents in the windings 32 and 33 will not be affected and the relayswill operate selectively only when a ground or excessive overload occursupon one or more of the feeder conductors.

I do not limit my invention to the particular structure and applicationillustrated, as it may be variously modified without departing from thespirit and scope of the invention as set forthin the appended claims.

I claim as my invention:

1. In a system of distribution, the combination with a plurality ofparallel-connected conductors and a series transformer for eachconductor, of an induction relay for each conductor severally having twow ndings that actuate the relay in accordance with the product of thecurrents traversing the same, means for connecting one term1- nal ofeach transformer to one termmal of one winding of the correspondmgrelay, and means for connecting the other relay windings in seriesbetween the common terminals of the transformers and the commonterminals of the first mentioned relay windings.

2. In a system of distribution, the combination with a plurality ofparallel-connected conductors and a series transformer for eachconductor, of a relay for each conductor severally having two windingsthat actuate the re ay in accordance with the product of the currentstraversing the same, means for connecting one terminal of one winding ofeach relay to one terminal of. itscorresponding transformer, and meansfor connecting the other relay windings in series between the commonterminals of the transformers and the common'terminals of the firstmentioned rela'y windings.

3. In a system of distribution, the combination with a plurality ofparallel .connected conductors and a series transformer for eachconductor, of a relay for each conductor severally having twocooperating windings that actuate the relay in. accordance with theproducts of the currents traversing the same, means for connecting oneterminal of one winding of each relay to one terminal of itscorresponding transformer, means for so connecting the other relaywindings in series across the transformers that current proportional tothe total current traversing the conductors traverses the same.

4. In a system of distribution, the combination with a plurality ofparallel-connect ed feeder conductors and a series transformer for eachconductor, of a relay for each conductor having two cooperating windingsthat actuate the relay in accordance with the product of the currentstraversing the same, means for connecting one terminal of one winding ofeach relay to one terminal of its corresponding transformer, means forconnectmg. the other terminals of said. windings together, and means forconnecting'the other relay windings in series between thecommonterminals of the transformers and the common terminals of thefirst mentioned relay windings.

5. In a system of distribution, the combination with -a plurality ofparallel-connected feeder conductors and a series itransformer for eachconductor, of a relay for} each conductor having two windings that"actuate the relay in accordance with the" product of the currentstraversing the same, I

means for connecting one winding of each relay in series with itscorresponding transformer, means for connectlng the other rethe currenttraversing that conductor and 9 the total current traversing all of thecon ductors exceeds a. predetermined value.

7. In a system of distribution, the combination with a'plurality ofparallel-connected feeder conductors, of a current transformer for eachconductor and a relay for each conductor energized from the currenttransformers in accordance with the product of the current traversingall the conductors and the current traversing the respective conductorsfor effecting the disconnection of'a conductor when the relay of thatconductor is energized in excess of a predetermined value.

8. In a system of distribution, the combi- 10 nation with a plurality ofparallel-connected feeder conductors, of a plurality of relays eachhaving a winding which is severally energized in accordance with thecurrent traversing a conductor and each having a second winding which isenergized in accordance with the sum of the currents traversing all ofthe conductors and means controlled by the relays for disconnecting aconductor in which the current is such that the product of the effectsdeveloped in the corresponding relay exceeds a predeterminedvvalue. A

9. In a system of distribution, the combination with a plurality ofparallel-connected feeder conductors, of a relay for each conductorhaving two cooperating windings, means for energizing one winding inaccordance with the current traversing the conductor, means forenergizing the other winding in accordance with the sum of the currenttrayersing all' of the conductors and means for disconnectmg a conductorwhen the product of the effects developed by the gree greater than apredetermined value, windings in the corresponding relay exand meansfort connecting the current transceeds a predetermined value. formers tothe windings to energize them 15 10. In a system of distribution, thecombirespectively, in accordance ith th r t; nation with a plurality ofparallel-connecttraversing the corresponding conductor and ed feederconductors, and a series transthe sum of the current traversing all ofthe former for each conductor, of a relay for conductors. each conductorhaving two cooperating In testimony whereof, I have hereunto 20 windingsthat actuate the relay in accordsubscribed my name this 23rd day ofAuance with the products of the currents travgust, 1916.

ersing the windings and serving to disconnect that conductor whenactuated to a de- CHARLES LE G. ORTESQUE.

